John thomas dempster



(No Model.) V

' J. T. DEMPSTER.

' GLOBE HOLDER FOR ARC LAMPS. 7

No. 514,417, Patented Feb. 6, 1594."

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Uwrrnn STATES FFKQ JOHN THOMAS DEMPSTER, OF SUMMIT, NEW JERSEY, ASSIGNOR TO SIGMUND BERGMANN, OF NEW YORK, N. Y.

GLOBE-HOLDER FOR ARC-LAM PS.

SPECIFICATION forming part of Letters latent No. 514,417, dated February 6, 1894.

Application filed February 13, 1893- Serial No. 462.Q48. (No model.)

To aZZ whom it may concern.-

Be it known that I, JOHN THOMAS DEM]?- STER, a subjectof the Queen of Great Britain, and a resident of Summit, State of New Jersey, have invented certain new and useful Improvements in Globe-Holders for Electric- Arc Lamps, of which the following is a specification. 1

My invention relates to globe holders for electric arc lamps, and the objects of my invention are to make the same, first; vertically adjustable, second; oircumferentially adjustable, third, incapable of falling off after adjustment although circumfercntially movable, and, fourth, capable of being firmly clamped in place in any adjusted position on the lower frame of the lamp, constructed to allow the lower carbon holder to be inserted from below into the same. I accomplish these objects by the means hereinafter described and claimed.

In the accompanying drawings forming part of this specification Figure 1 is a plan of a construction of globe holder, embodying my invention. Fig. 2 is a side elevation, and Fig. 3 is a vertical sectional view of Fig.2.

Referring to the drawings 1 represents the lower lamp frame constructed with a hollow cylindrical part through which the lower carbon holder is inserted for holding the lower carbon. The carbon holder is not shown in the drawings as it constitutes no part of this invention. This lamp frame is formed with a cylindrical extension which carries a projection 2 the function of which will presently appear. The globe holder 3, provided with several clamping screws 4 as usual, is formed with a. downwardly projecting sleeve to fit over and slide up and down on the lamp frame extension '1. The inner peripheryof the sleeve of the globe holder is provided with a vertical groove 5, of a width and depth to allow it to receive the projection 2 before referred. to, so that when the groove ofthe holder and projection of the extension are in line with each other the globe holder can be moved up on the lamp frame extension. The

globe holder 3 is provided with a screwthreaded lug 6 carrying a locking and clamping screw 7 which projects into the vertical notch of the globe holder.

When the globe holder has been moved up on the lamp frame extension so thatthe screw 7 is above the projection 2, the downward removal or falling off of the globe holder is prevented by screwing in the screw '7 suiiiciently to cause it to abut against the projection 2 when the latter engages the groove as shown in Fig. 3. The globe holder may be elevated above the projection 2 and turned circumferentiallyand allowed to rest on said projection. It may also be firmly clamped in said position by the screw 7, or it may be adjusted at any higher level and there held in place as shown in Fig. 2. The screw 7 therefore serves the two purposes of locking the globe holder to the lamp frame extension, allowing circumferential movement, and of clamping it firmly in any desired position to said extension, through which the lower carbon holder passes.

Having thus described my invention, what I claim, and desire to secure by United States Letters Patent, is

1. The combination with the lower lamp frame provided with a projection, a globe holder provided with a longitudinal groove to cooperate with said projection, and a clamping screw to clamp the globe holder in any desired position, substantially as described.

2. The combination with the lower lamp frame constructed with a hollow cylindrical 'part, and provided with a projection, a globe holder provided with an inner longitudinal groove to cooperate with said projection, and a clamping screw for clamping the globe holder to the lamp frame, substantially as described.

3. The combination with the lower lamp frame provided with a projection, a globe holderprovided with an inner longitudinal groove to cooperate with said projection, said globe holder constructed so as to be elevated above said projection, and aclamping screw, substantially as described.

Signed at New York, in the county of New York and State of New York, this 2d day of February, A. D. 1893.

JOHN THOMAS DEMPSTER. 

